This invention relates to processes for decolorizing polyalkylene polyamines.
Polyalkylene polyamines are well known commercial compounds having a variety of uses. The end use of these compounds influences the amount of color which is desirable in the product to be sold. Methods to purify and thereby reduce color of polyalkylene polyamines is thus very important for both a producer and an end user.
U.S. Pat. No. 3,723,529 to Pitts et al., dated Mar. 27, 1973, sets forth such a method. The disclosed process entails passing polyethylene polyamines through a carbon bed and then distilling the effluent. Pitts et al. explain that treatment with only carbon failed to decolorize the polyamines at temperatures of at least 190.degree. C. and, in fact, led to more highly colored products in some cases. Since distillation processes are energy intensive, however, a process which facilitates removal of color in polyalkylene polyamines without such a step is highly desirable.